Carburetor for internal combustion engines



May 30, 1961 M. E. JONES 2,986,381

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Sept. 8, 1959 FIG.2.

4 Sheets-Sheet 1 INVENTOR. MALDWYN E. JONES mi a ATTORNEY May 30, 1961M. E. JONES CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filedv Sept. 8,1959 4 Sheets-Sheet 2 FIGS.

INVENTOR. MALDWYN E. JONES AT RNEY y 0, 1961 M. E. JONES 2,986,381

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Sept. 8, 1959 4Sheets-Sheet 3 *3' /4 3 6 11 GD 8 64- 57 H 2 V} v 64 9 q) 33 I L /59 28I l 1 44 I l 1 15 I I IQ mz -56 v F I G. 6

INVENTOR. MALDWYN E. JONES ATTORNEY.

y 1961 M. E. JONES 2,986,381

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Sept. 8, 1959 4Sheets-Sheet 4 FIG.7.

INVENTOR. MALDWYN E. JONES ATTORNEY United Smtes Patent CARBURE'IOR FORINTERNAL COMBUSTION ENGINES Maldwyn E. Jones, Scottsdale, Ariz.,assignor to ACF Industries, Incorporated, New York, N.Y., a corporationof New Jersey Filed Sept. 8, 1959, Ser. No. 838,492

6 Claims. (Cl. 261-41) This invention relates to carburetors forinternal combustion engines, and more particularly, to a carburetorembodying means for more accurately controlling the proportion of fueland air supplied to an engine to provide greater economy and betterengine performance.

The present invention contemplates the provision of a carburetorparticularly adapted for use on outboard motors for boats. For manyyears, outboard motors were of relatively small horsepower and consumedsmall quantities of fuel. Therefore, fuel economy was not an importantfactor. During recent years, the market is being supplied with highhorsepower outboard motors which consume large quantities of fuel. Itis, therefore, an object of the invention to provide a carburetor whichmore accurately controls the fuel mixture supplied to the engine toeffect greater economy of operation and better engine performance.

Another object of the invention resides in the provision of a commonmanually operable control mechanism for accurately proportioning thefuel and air mixture supplied to meet engine requirements throughout therange of engine speeds.

A further object of the invention resides in the provi sion of acarburetor embodying an idle fuel system and a main fuel systemselectively operable responsive to manual operation of a throttle valve,the main fuel system embodying a stepped fuel metering rod axiallymovable within a main fuel nozzle.

Another object of the invention resides in the provision of a carburetorembodying a fuel well surrounding the main fuel nozzle to supply anadditional quantity of fuel and air to the main nozzle during fastacceleration of an engine.

Another object of the invention is to provide a carburetor which isinexpensive in construction and reliable in operation throughout thespeed range of an engine.

The invention embodies other novel features, details of construction andarrangement of parts which are hereinafter set forth in thespecification and claims and illustrated in the accompanying drawings,forming part thereof, wherein:

Fig. 1 is a top plan view illustrating a carburetor embodying featuresof the invention.

Fig. 2 is an elevation showing one side of the carburetor.

Fig. 3 is an elevation showing the other side of the carburetor.

Figs. 4 and S are elevations showing opposite ends of the carburetor.

Fig. 6 is a longitudinal section taken along the line 6-6 of Fig. 1.

Fig. 7 is a transverse section taken along the line 7-7 of Fig. 2.

Fig. 8 is a fragmentary section taken along the line 8--8 of Fig. 3.

Fig. 9 is a fragmentary section taken along the line 9-9 of Fig. 4showing the throttle valve in closed position.

Patented May 30, 1961 Fig. 10 is a fragmentary section illustrating themetering rod as positioned within the main fuel nozzle to control theflow of fuel therethrough.

Referring now to the drawing for a better understanding of theinvention, the carburetor is shown in Figure 6 specifically ascomprising a body 2 having a horizontal mixture conduit 3 provided withan air inlet 4, an outlet 6, and a venturi 7 having a throat 8. A flange1 (Figs. 1 and 4) is provided on the outlet end of the body forattachment to an engine inlet manifold 5.

A choke valve shaft 9 is journalled in bearing apertures formed in thebody 2 to support a choke valve 11 for pivotal movement within the airinlet 4. The choke valve 11 is normally maintained in its full openposition, as iudicaed in Fig. 6, by means of a torsion spring 12 (Fig.5) having one end thereof secured to the shaft 9 and its other endsecured to the body 2. The choke valve 11 is adapted to be pivoted toits closed or choke position by manual movement of an arm 13 secured toone end of the choke shaft 9.

A throttle shaft 14 is journaled in bearing apertures formed in the body2 to support a throttle valve 16 for pivotal movement in the outlet 6,the shaft being engaged against axial movement relative to the body 2 bymeans of a plate 17 secured to the body by a screw 18 and having an endthereof engaged in an annular groove 19 formed in the shaft. A manuallyoperable control arm 21 is secured to one end of the throttle shaft 14to control the proportion and quantity of fuel and air supplied to theengine. The throttle valve 14 is biased toward its closed position bymeans of a helical torsion spring 22 having one of its ends engaging thebody 2 and its other end engaging the control arm 21.

The body 2 is provided with a downwardly projecting tubular stem 23having its lower end internally threaded at 24 for engagement with thelower externally threaded end 25 of a main fuel nozzle 26, asillustrated in Fig. 6. The lower end of the nozzle 26 is slotted at 27for engagement by a screw driver during assembly to rotate the nozzleinto tight leakproof engagement against an annular shoulder 28. Theportion of the nozzle between its threaded end 25 and the shoulder 28 isreduced in diameter to define with the stem 23 a fuel well 29. Aplurality of ports 31 are formed in the nozzle for the passage of fuelinto and out of the lower end of the well 29, and an air bleed passage32 (Fig. 8) is formed in the body 2 leading from atmosphere to the upperend of the well.

The upper end of the main fuel nozzle 26 projects upwardly into theventuri 7 posterior to the throat 8 and is provided with a plurality oflow speed ports 33. A fuel metering orifice 34 is formed in the lowerend of the main fuel nozzle 26 to receive the lower end 36 of a meteringrod 37. The lower end of the metering rod 37 engages a headed pin 38which is resilient supported upon a helical compression spring 39 seatedat its lower end in a fuel bowl mounting screw 41. The upper end of themetering rod 37 extends through a bearing 40 press-fitted into anopening 42 in the body 2. v

The lower portion of the body 2 is formed with a downwardly projectingannular flange 43 having a recess 44 therein to receive the rim portionof a cup-shape fuel bowl 46, the bottom 45 of the bowl having anaperture 47 to receive the screw 41, and an annular inturned head 48concentric with said aperture. During assembly, the screw 41 firstengages the bowl against a gasket 49 in the recess 44, and then forcesthe bowl bottom 45 against the stem 23.

A hollow ring-shape float 51 is mounted on a pin 52 (Fig. 7) for pivotalmovement within the fuel bowl to actuate a conventional needle valve 53to control the flow of fuel through an inlet 54 and valve port 56 intothe position.

3- bowl. The float and valve are adapted to coact to maintain asubstantially constant fuel level within the bowl. An air vent 75 leadsthrough the body 2 to the bowl. Fuel is supplied from a tank T (Fig. 1)through a con- .duit'57 and pump P to the fuel inlet 54. A stop pin 58(Fig. 6) is provided on the stem 23 to limit downward movement of thefloat 51. Fuel passes from the bowl through ports 55 into a chamber 60in the stem 23 below the orifice 34.

An idle fuel system is shown as comprising a hollow idle tube 59 (Fig.6) extending vertically from within the fuel bowl 46 through the venturithroat 8 to an idle passage 61 in the body 2, the lower end of the tube59 being disposed below the fuel level in the bowl and provided with arestricted orifice 62. The idle passage 61 extends to an idle port 63(Fig. 7) leading into the mix- I hire conduit 3 anterior to the edge ofthe throttle valve 16 when the latter is in its closed position, asillustrated in Fig. 9. Apertures 64 are provided in the throttle valve16 for the passage of air when the latter is in its closed An idleadjustment screw 66 (Fig. 4) is threaded into the body 2 to regulate theflow of fuel through the idle passage 61.

A cam 67 having an inclined surface 68 is provided on the control arm 21for slidable engagement along the upper end of the metering rod 37responsive to rotational movement of the control arm, whereby themetering rod is moved axially to vary the quantity of fuel passingthrough the orifice 34. The lower end of the metering rod may beprovided with one or more sections of different diameters, as shown inFig. 10, or may be formed with a long tapering surface, whereby the flowarea through the orifice 34 may be varied responsive to axial movementof the metering rod.

In the operation of the carburetor thus shown and described, fuel isforced from the tank T and through the conduit 57 to the intake 54 bythe pump P, and thence through the valve port 56 into the fuel bowl 46under control of the float actuated needle valve 53 to maintain the fuelat a predetermined level within the bowl.

During idle operation of an engine, the throttle valve 16 is in itsclosed position and fuel is supplied to the mixture conduit 3 throughthe idle tube 59, passage 61, and idle port 63, under control of theidle adjustment screw 66. To effect a slight increase in engine speed,the control arm 21 is manually pivoted to move the throttle valve 16 toa part open position to cause fuel to be drawn upwardly through the mainnozzle 26 and out through the ports 33 into the mixing conduit 3.

Further gradual pivotal movement of the control arm 21 moves thethrottle valve 16 toward its full open position and permits the spring39 to raise the metering rod 37 as the latter passes along the inclinedsurface 68 on volume of fuel flowing through the orifice 34 for passageupwardly and out through the upper end of the main nozzle 26 into thecenter of the mixture conduit 3.

When the throttle valve =16 is opened quickly to provide rapidacceleration of an engine, additional fuel and air is drawn from thewell 29 through the openings 31 into the main nozzle 26 for dischargetherefrom into the mixing conduit 3.

By providing a manually operable mechanical means 1 forsimultaneouslyoperating the throttle valve and meter- 'ing'rod, the quantity andproportion of fuel and air may be accurately controlled to effect amaterial saving of from 10% to 30% in fuel and an improvement in engineperformance during idling, part throttle, acceleration, and fullthrottle. In the operation of a boat equipped with two 50 or 60horsepower engines, it will be appreciated that such a saving in fuel isof major importance, as

-- it decreases the cost of operation and permits an increase in therange a boat may travel when supplied with a predetermined quantity offuel. Certain structures have been described herein which will fulfillall the objects of the present invention, but it is contemplated thatother modifications will be obvious to those skilled in the art whichcome within the scope of the invention as defined by the appendedclaims.

I claim:

1. A carburetor for an internal combustion engine and comprising a bodyincluding a mixture conduit adapted to be horizontally disposed andhaving an inlet, an outlet and a venturi surface therebetween, athrottle valve in said outlet, a throttle shaft journaled in said bodyand secured to said throttle valve, a fuel bowl mounted on said body,means forming a tubular fuelpassage extending from. said body andterminating at one .end in said bowl, a main fuel nozzle mounted in saidfuel passage means and projecting through said ventnri surface into saidmixture conduit, means forming in said terminating end of said fuelpassage a metering orifice, a movable metering rod extending throughsaid nozzle and having a tapered end extending through said orifice tovary the flow area therethrough, an opening from said fuel bowl intosaid fuel passage for the flow of fuel from said bowl upwardly throughsaid nozzle, said fuel passage means and siad nozzle defining an annularwell provided at its upper end with an air bleed passage, said nozzlehaving an opening leading to the lower end of said well above saidmetering orifice and adjacent to said tapered metering rod end, andmechanical means to actuate said throttle valve and metering rodsimultaneously to variably proportion the fuel air mixture supplied tosatisfy engine requirements at different speeds, said mechanical meanscomprising a spring biasing said metering rod in one direction, acontrol arm secured to said throttle shaft and a. cam on said armengaging the other end of said metering rod for moving said metering rodagainst said biasing spring.

2. A carburetor for an internal combustion engine and comprising a bodyincluding a horizontal mixture conduit having an inlet, an outlet and aventuri surface there between, a throttle valve in said outlet, athrottle shaft journaled in said body and secured to said throttlevalve. a fuel bowl mounted on said body, a tubular stem depending fromsaid body into said bowl, a hollow screw extending through said fuel andthreaded into said stem to fasten said fuel bowl to said stem, a mainfuel nozzle mounted in said stern and projecting through said venturisurface into said mixture conduit, a metering orifice adjacent to thelower end of said stem, a movable metering the cam 67 to therebyincrease the flow area and the rod extending through said nozzle andhaving a tapered end extending through said orifice therein to vary theflow area through said orifice, and stem having an opening for the,passage of fuel from said bowl upwardly throughsaid nozzle, said stemand nozzle defining an annular well provided at its upper end with anair bleed passage, said nozzle having an opening leading to the lowerend of said Well above said metering orifice and adjacent to saidtapered metering rod end, and mechanical means to actuate said throttlevalve and metering rod simultaneously to variably proportion the fuelair mixture supplied to satisfy engine requirements at different speeds,said mechanical means comprising a spring means within said hollow screwand in contact with said tapered metering rod end for biasing saidmetering rod in one direction, a control arm secured to said throttleshaft, and a cam on said arm engaging the other end of said metering rodfor moving said metering rod against said biasing spring means. a

. through said fuel bowl and threaded into said stem to surface intosaid mixture conduit, said fuel nozzle having a metering orificeadjacent to its lower end, a movable metering rod extending through saidnozzle and having a tapered end extending through said orifice thereinto vary the flow area through said orifice, said stem having an openingfor the passage of fuel from said bowl upwardly through said nozzle,said stem and nozzle defining an annular well provided at its upper endwith an air bleed passage, said nozzle having an opening leading to thelower end of said Well above said metering orifice and adjacent to saidtapered metering rod end, and mechanical means to actuate said throttlevalve and metering rod simultaneously to variably proportion the fuelair mixture supplied to satisfy engine requirements at different speeds,said mechanical means comprising a spring means within said hollow screwand in contact with said tapered metering rod end for biasing saidmetering rod in one direction, a control arm secured to said throttleshaft, a cam on said arm engaging the other end of said metering rod formoving said metering rod against said biasing spring means, and a springconnected to said control arm to move said cam and metering rod againstsaid biasing spring means.

4. A carburetor for an internal combustion engine and comprising a bodyincluding a horizontal mixture conduit having a venturi surface therein,a throttle valve in said mixture conduit, a throttle shaft journaled insaid body and secured to said throttle valve for moving said throttlevalve from an open to closed position, a fuel bowl mounted on said body,a tubular structure depending from said body into said bowl, a main fuelnozzle mounted in said tubular structure and projecting through saidventuri surface into said mixture conduit, a metering orifice adjacentto the lower end of said tubular structure, a movable metering rodextending through said nozzle and having a tapered end extending throughsaid orifice therein to vary the flow area through said orifice, saidtubular structure having an opening for the passage of fuel from saidbowl upwardly through said nozzle, means to actuate said throttle valveand metering rod to variably proportion the fuel air mixture supplied tosatisfy engine requirements at different speeds, and an idle fuel systemcomprising an idle tube extending through said venturi surface andacross said mixture conduit, one end of said idle tube extending intosaid fuel bowl and the other end thereof terminating in said body, saidbody having an idle port opening into said mixture conduit anterior tosaid throttle valve in closed position and an idle passage leading fromsaid other end of said idle tube to said idle port.

5. A carburetor for an internal combustion engine and comprising a bodyincluding a mixture conduit having a venturi surface therein, a throttlevalve in said mixture conduit, a throttle shaft journaled in said bodyand secured to said throttle valve for moving said throttle valve froman open to a closed position, a fuel bowl mounted on said body, atubular stern depending from said body into said bowl, a main fuelnozzle mounted in said stem and projecting through said venturi surfaceinto said mixture conduit, said fuel nozzle having a metering orificeadjacent its lower end, a movable metering rod extending across saidmixture conduit and through said nozzle and having a tapered endextending through said orifice therein to vary the flow area throughsaid orifice, said stem having an opening for the passage of fuel fromsaid bowl upwardly through said nozzle, means to actuate said throttlevalve and metering rod to variably proportion the fuel air mixturesupplied to satisfy engine requirements at different speeds, and an idlefuel system comprising an idle tube extending through said venturisurface and across said mixture conduit parallel to said metering rod,one end of said idle tube extending into said fuel bowl and the otherend thereof terminating in said body, said body having an idle portopening into said mixture conduit anterior to said throttle valve inclosed position and an idle passage leading from said other end of saididle tube to said idle port.

6. A carburetor for an internal combustion engine and comprising a bodyincluding a mixture conduit adapted to be horizontally disposed andhaving a venturi surface therein, a throttle valve in said mixtureconduit, a throttle shaft journaled in said body and secured to saidthrottle valve for moving said throttle valve from an open to closedposition, a fuel bowl mounted below said body, a tubular structuredepending from said body into said bowl, a main fuel nozzle mounted insaid tubular structure and projecting through said venturi surface intosaid mixture conduit, means forming a metering orifice adjacent to thelower end of said tubular structure, a movable metering rod adapted tobe vertically disposed and extending across said mixture conduit throughsaid nozzle and having one tapered end extending through said orificetherein to vary the flow area through said orifice, means slidablymounting the other end of said metering rod in the upper portion of saidbody, and an idle fuel system comprising an idle tube adapted to bevertically disposed and extending through said venturi surface andacross said mixture conduit, one end of said idle tube extending intosaid fuel bowl and the other end thereof terminating in the upperportion of said body, said body having an idle port opening into saidmixture conduit anterior to said throttle valve in closed position andan idle passage leading from said other end of said idle tube aroundsaid other metering rod end to said idle port.

References Cited in the file of this patent UNITED STATES PATENTS1,579,600 Durante Apr. 6, 1926 1,612,352 Boehner Dec. 28, 1926 1,858,057Pilling May 10, 1932 1,967,708 Ericson July 24, 1934 2,297,109 MoseleySept. 29, 1942 2,405,563 Enright Aug. 13, 1946

